The present invention relates to a spring roller, and more particularly it relates to a roller in which a roller shaft and a roller body are interconnected by elastic means so as to permit relative rotational movement between the roller shaft and the roller body.
In general, in an apparatus comprising a pair of rollers and a sheet wound on said rollers, in order to absorb or eliminate any slack of the sheet generated while the sheet is shifted from one roller to the other, a tension bar is used. However, it is not desirable to use this tension bar in such an apparatus, since the tension bar makes the apparatus complicated. Further, amount by which slack of the sheet can be eliminated is limited by the use of a tension bar.
Particularly, a tape driving apparatus previously proposed by the Applicant (refer to Japanese Patent Disclosure No. 171960/85) comprises a pair of rollers (first and second rollers), a tape or sheet wound from its one end of the first roller with one face thereof inside and wound from the other end thereof on the second roller with the other face of the sheet inside, and driving means for selectively driving the first roller or the second roller to shift the sheet from one roller to the other. When this tape driving apparatus is adapted to an item changing mechanism of a multi-purpose codeless input machine, a large number of items are printed, written or disposed on both surfaces of the sheet, and the sheet is shifted by the above-mentioned driving means to position a desired item in a predetermined visual position. However, since the multi-purpose codeless input machine itself is one part of the terminal equipment of a computer system, the item changing mechanism of the input machine must be compact, and accordingly it is also undesirable to use a tension bar in such an item changing mechanism.